double f(double lambda1, double lambda2, double phi1, double phi2) {
double r10799172 = lambda1;
double r10799173 = lambda2;
double r10799174 = r10799172 - r10799173;
double r10799175 = sin(r10799174);
double r10799176 = phi2;
double r10799177 = cos(r10799176);
double r10799178 = r10799175 * r10799177;
double r10799179 = phi1;
double r10799180 = cos(r10799179);
double r10799181 = sin(r10799176);
double r10799182 = r10799180 * r10799181;
double r10799183 = sin(r10799179);
double r10799184 = r10799183 * r10799177;
double r10799185 = cos(r10799174);
double r10799186 = r10799184 * r10799185;
double r10799187 = r10799182 - r10799186;
double r10799188 = atan2(r10799178, r10799187);
return r10799188;
}